These teachings relate generally to chromic luminescent objects, and more particularly, to the preparation and use of one or more chromic luminescent compositions that are incorporated into or onto one or more portions of the object, such that brightness of the one or more portions of the object are substantially modulated as a function of incident electromagnetic radiation. In addition to brightness, the one or more chromic luminescent compositions may also afford color of the one or more portions of the object to be substantially modulated as a function of incident electromagnetic radiation. Further, frequency of the object may also be substantially altered through substantially modulated brightness alone or brightness and color of one or more adjacent portions of the object as a function of incident electromagnetic radiation.
The human eye contains two types of photoreceptors, rods and cones. The rods are more numerous, some 120 million, and perceive brightness. The cones, of which there are 6 to 7 million, provide the eye's sensitivity to color. As a consequence, given the significantly larger number of receptors that detect variations in brightness, minimizing detection of an object with any adaptive camouflage scheme should encompass the ability to vary at least brightness in addition to color. Unfortunately, today's camouflage systems do not provide a mechanism to account for varying brightness, as well as frequency and/or color if desired, so as to more effectively reduce contrast of an object as the local environment and/or terrain changes, and therefore are unable to provide optimum concealment.
Currently, the majority of color renditions onto objects are achieved by deploying absorptive-only, non-luminescent compositions. Although such absorptive-only, non-luminescent compositions can achieve a wide color gamut, these compositions are static, that is, once applied they remain the same and hence cannot change color as the incident electromagnetic radiation changes. Furthermore, as incident electromagnetic radiation changes, such compositions do not enable variations in brightness of the object or additionally, the frequency of the object. As a result, the use of these compositions is substantially limiting.
Today's camouflage systems are sophisticated combinations of colored macro and/or micro patterns, as described in U.S. Pat. No. 6,805,957, that are developed to address disruption of shape and background matching for the purpose of concealment. These systems generally use absorptive pigments that subtract a certain fraction of incident electromagnetic radiation to produce a desired reflectance value rendered as a repeat pattern so as to achieve a brightness level similar to that of the selected surrounding for which concealment is warranted. Ideally, movement of an object from a high frequency domain, such as a woodland terrain, to a low frequency domain, such as flat terrain, should be accompanied by a diminished pattern and increased brightness in order to minimize the object's contrast with the background. However, this does not occur with the current camouflage systems since, once applied, they produce a reflectance value and pattern frequency that are static, i.e. they will not change as the environment and/or terrain changes, and are therefore unlikely to be as effective throughout the 24 hr day/night cycle, as well as where different terrains are encountered. It can be appreciated that when the environment is darker the color(s) of the object should become less bright to better blend in with the surroundings and conversely, for very bright surroundings, the color(s) of the object should be brighter.
Furthermore, although there have been attempts at adaptive camouflage systems that utilize various triggers, such as those cited in U.S. Pat. Nos. 5,985,381 and 5,144,877, such technologies rely on the varying absorptive properties of dyes formed via molecular rearrangements following either sunlight exposure or temperature change to affect color change, i.e. going from a colorless or light colored state to a darker colored state. These teachings provide an additive color function on top of the base static camouflage colors and as a result, do not then have the ability to modulate brightness so as to minimize contrast.
Given the existing camouflage systems being employed onto objects, there is, therefore a need for chromic luminescent objects that utilize chromic luminescent compositions that are non-static and readily adaptable to incident electromagnetic radiation resulting from the environment or terrain for which the object is deployed. Thus, it also desirable that the chromic luminescent objects utilize chromic luminescent compositions that modulate at least brightness, or additionally modulate frequency and/or color, as a function of incident electromagnetic radiation, so that optimum concealment of the object is achieved relative to varying surrounding environments or terrains the object encounters.